I. Field of the Invention
The present invention relates to a device for spinning endless filaments of synthetic polymers.
II. Description of the Prior Art
When spinning endless filaments out of synthetic polymers, such as polyamides, polyesters or polypropylene, one trys to keep the capacity of each spin position as high as possible. Such a spin position consists of a spin head, spin pumps (dosing pumps) and spinnerets in spinneret holders, blowing chamber, spin finish device and winder. Usually, several spin heads are combined to a spin beam, likewise the winders, arranged below, to a winding machine. A melt distributor is preconnected to the spin heads, a melting device to this melt distributor, nowadays usually is an extruder. The higher the capacity per spin position, the better the exploitation of this device, and the lower investment costs for a synthetic fiber plant. This results in the fact that up to 16 ends are produced per spin position, e.g., by spinning 16 ends out of a spin head, fitted with four spinneret holders (spin packs); each spinneret holder being fitted with two spinnerets, which are divided up semicircular or kidney-shaped, into two spinnerets each, or the spin head consists of eight spinneret holders with two spinnerets each so that in both cases altogether 16 melt streams are produced which are individually fed. Subsequently, 16 filaments are leaving the spin head. A filament, also called an end, means several single filaments or capillaries which are combined to one filament and then wound up. On the one hand, the limitation of increasing the capacity per spin position is to be seen in the decrease of filter surface in front of the spinnerets caused by increasing the filament numbers, and on the other hand in the limited number of bobbins to be wound per winding axis. When increasing the speed, i.e., a further possibility to increase capacity per spin position, handling of a great number of filaments becomes more and more difficult.
Parallel to the development of spin equipment suitable for the highest possible number of filaments, spin speed was increased. This resulted in a sudden further development of a spin system when it became obvious that not only economy of spinning was influenced, but the filament itself, when exceeding a certain speed.
In the case of POY spinning, i.e., preoriented yarn, within a range of more than 3.000 m/min and high-speed spinning in a range of up to 6.000 m/min winding speed, it is usual to spin either four and eight or six and twelve ends per spin head/spin position. Thus, four ends--in the case of a titer of 150 denier (relevant to 165 dtex)--are spun out of four spinnerets in four spinneret holders; in the case of a smaller titer of 75 den (83 dtex) eight ends out of eight spinnerets in four spinneret holders. Thus, the capacities are nearly the same whereas in case of four end spinning of 75 den, the throughput would only be half of it. In the last few years oil depending raw materials, such as synthetic polymers, have become more and more expensive. Furthermore, the clothing industry tends towards lighter clothes. Consequently, finer titers were produced, i.e., from 75 den to 40 den, and, in the case of polyester, even to 30 den. In the case of polyamide, hosieries are already of 20 den and finer.